Final answer:
Cascade, or stand-up, pin curls are designed to add volume to the hair. They create a cascading effect by setting the hair vertically or diagonally, which emphasizes body and fullness in the hairstyle. The correct option is 1.
Step-by-step explanation:
Cascade, or stand-up, pin curls are used to create volume in the hair design. This hairstyling technique involves curling a section of hair with a hairpin or curling tool and setting it vertically or diagonally on the head.
The setup allows the hair to 'cascade' down, giving the impression of more volume and body. While pin curls can also create curls, the context of 'cascade' or 'stand-up' specifically refers to enhancing volume rather than creating curliness, straightness, or shine.
Hence, Option 1 is correct.